Damping device in a structure and damping construction and damping method using those devices

ABSTRACT

A damping device has a liquid vessel into which the liquid is injected having the flattening wave motion water surface formed in such a manner that the wave motion direction of the wave motion water surface is a strecher one, damping members are provided in order to damp the sloshing of liquid in the liquid vessel, and wave dissipation devices are disposed at the portion which isn&#39;t always soaked in liquid in the liquid vessel. Accordingly, the vibration in a construction occurring by wind, earthquake and the like is absorbed by means of viscosity resistance occurring between liquid and damping member, and the vibration is restricted. Moreover, damping performance can be efficiently exercised by providing various kinds of installation forms.

This is a Divisional application of Ser. No. 07/216,496, filed on July8, 1988.

BACKGROUND OF THE INVENTION

The present invention relates to the damping device for preventing thehorizontal vibration of a structure which proceeds from wind andearthquake by disposing it on the upper portion of a structure and thedamping structure and damping method using those devices.

In U.S. PAT. No. 4,226,554, the following proposal is advanced. It isthat the horizontal vibration of a structure which proceeds fromearthquake, wind and the like is prevented in such a manner that dampingdevices comprising liquid vessels into which the liquid having openwater surface is injected are disposed on the upper portion of thestructure.

However, the founded technique isn't present relating the concreteinstallation forms and the efficient internal constitution of a dampingdevice and the like, and such a technique is desired.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a dampingdevice having internal constitution and the installation forms capableof exercising efficient damping performance, and the dampingconstitution and damping method using those devices so as to solve theabove-described defects.

That is, the present invention is comprised of a liquid vessel, intowhich the liquid is injected, having a flattening wave motion watersurface formed in such a manner that the wave motion direction of thewave motion water surface is the stretcher one, damping members such asmeshes, partition walls and projections for damping the sloshing of theliquid in the liquid vessel and wave dissipation devices provided at theportion which isn't always soaked in the liquid of the liquid vessel.

According to the present invention, the vibration which proceeds fromwind and earthquake in a structure such as a multistory building andtower can be efficiently absorbed by sloshing the liquid in each dampingdevice. And, since its constitution has no mechanical moving part by aliquid vessel, liquid and the like, it has reliability toward the changewith the passage of time in comparison with a mechanical dampingorganization. And, it can be easy to perform inspection and maintenance.If high wave occurs in the liquid of a vessel by operating the sloshingwhich the amplitude is broad, its energy is efficiently absorbed bymeans of wave dissipation devices. Therefore, the cycle of liquid has nodisorder, and its device is sufficiently reliable.

The damping device is comprised of a liquid vessel, into which theliquid is injected, having the flattening wave motion water surfaceformed in such a manner that the wave motion direction of the wavemotion water surface is a stretcher one, and damping member such asmeshes, partition walls and projections for damping the sloshing of theliquid in the liquid vessel. With the above-described constitution, theplural damping devices are disposed in such a manner that the stretcherdirection of the liquid vessel of each damping device faces at least twohorizontal directions of the structure.

According to this constitution, the vibration in the horizontaldirection which proceeds from wind and earthquake in a structure such asa multistory building and tower can be efficiently absorbed relatingeach direction by the sloshing of the liquid in each damping device.

Furthermore, the damping device is comprised of a liquid vessel, intowhich the liquid is injected, having the flattening wave motion watersurface formed in such a manner that the wave motion direction of thewave motion water surface is a stretcher one, and damping member such asmeshes, partition walls and projections for damping the sloshing of theliquid in the liquid vessel. With the above-described constitution, thedamping devices are disposed on the upper portion of a structure in sucha manner that the damping devices at the side being distant from thecenter of rigidity of the structure such as side face are more than thatof the reverse side.

According to this constitution, in case that the center of rigidity of astructure is shifted from the center of gravity in the horizontal plane,its vibration energy can be absorbed as equal as possible. And,torsional vibration with the center of rigidity as its center can beefficiently absorbed.

Moreover, in an existing structure being provided an elevated water tankon the upper portion such as a multistory building and tower, theconstitution is such that resistance member such as meshes, partitionwalls and projections are provided in the elevated water tank and wavedissipation devices are provided at the upper portion of the elevatedwater tank. Then, the vibration in an existing structure is restrictedby the resistance between the resistance member and water which isstocked in the elevated water tank.

According to this constitution, the damping function toward thevibration by wind and earthquake can be added only by providingresistance member in an elevated water tank which is provided at anexisting structure such as a multi-story building and tower. And, sincethe installation activity of the complicated machinery isn't needed atall, the structural body in the shape of changing the size of the liquidvessel. In this case, the damping device is comprised of the liquidvessel having the liquid injected in the shape of forming open-level.

Then, each position being provided the liquid vessel has no uselessspace. Therefore, the limited space of a structure can be efficientlyutilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view for showing an example of the structure to which thisinvention is applied;

FIG. 2 is a strabismus view for showing an example of the arrangement ofdamping devices;

FIG. 3 is a top view for showing an embodiment of a damping device;

FIG. 4 is a front sectional view of the damping device in FIG. 3;

FIG. 5 is a top view for showing the other embodiment of a dampingdevice;

FIG. 6 is a front sectional view of a damping device in FIG. 5;

FIG. 7 is a top view for showing another embodiment of a damping device;

FIG. 8 is a front sectional view of a damping device in FIG. 7;

FIG. 9 is a strabismus view for showing an example of the otherarrangement of damping devices;

FIG. 10 is a top view of FIG. 9;

FIG. 11 is a top view for showing an example of another arrangement ofdamping devices;

FIG. 12 is a top view for showing an example of another arrangement ofdamping devices;

FIG. 13 is a front elevation for showing an other example of thestructure using damping devices;

FIG. 14 is a top view for showing an example of the another arrangementof damping devices;

FIG. 15 is a top view for showing an example of another arrangement ofdamping devices;

FIG. 16 is a front sectional view for showing another example of adamping device;

FIG. 17 is a top view for showing an example of the arrangementconstruction of damping devices;

FIG. 18 is a top view for showing the other example of the arrangementconstruction of damping devices;

FIG. 19 is a front sectional view for showing another example of adamping device;

FIGS. 20 through 22 are views for showing some kinds of vibration modesof a structure;

FIG. 23 is a front elevation for showing an embodiment of a dampingstructure; and

FIG. 24 is a front elevation for showing another embodiment of a dampingstructure.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The multistory building 1 which is a kind of a structure has astructural body 3 which is built on the ground 2 as shown in FIG. 1, andthe plural damping devices 5 are disposed on the apical portion 3a ofthe structural body 3. Two damping devices 5 are disposed in the shapeof crossing rectangularly each other as shown in FIG. 2. Each dampingdevice 5 has a liquid vessel 5a of which a lid member 5g is provided onthe upper portion and the form in the flat of the vessel 5a is rectangleas shown in Figs. 3 and 4. The liquid 5b which is water, or liquidhaving the same viscosity with water or higher viscosity than water isinjected into each liquid vessel 5a. Wave motion water surface 5foccurring by sloshing of the corresponding liquid 5b is formed in theshape of rectangle as flattening shape in the liquid vessel 5a by meansof the injected liquid 5b as shown in FIG. 2. The meshes 5c comprisingstainless steel, vinylon, high efficiency fiber and the like areprovided at two deck, upper and lower portions as shown in FIG. 4 asdamping member at both sides, right and left in the liquid vessel 5a inFIG. 3. And the mesh 5c is perpendicularly provided at the centerportion of FIG. 4. The wave dissipation devices 5h and 5h are providedat both sides of the lid member 5g at the upper portion of the liquidvessel 5a. The wave dissipation device 5h is composed of porous memberforming a block by scrap iron, crushed stone, metal chip and the like orthe aggregation of meshes provided in the shape of superimposing pluralnumber of meshes 5k in the horizontal direction as shown in FIG. 19.

With the above-described constitution of a multistory building 1, whenthe structural body 3 vibrates by earthquake, gust and the like, thedamping device 5 provided at the apical portion 3a also vibrates. Then,the liquid 5b in the damping device 5 sloshes in the stretcherdirections WD of the wave motion water surface 5f in the shape ofsynchronizing with the vibration of the structural body 3 as shown inFIGS. 3 and 4. That is, the liquid 5b easily starts sloshing accordingto the vibration of a multistory building 1 by harmonizing the sloshingcycle of the liquid 5b (The sloshing cycle of the liquid 5b is decidedby the length L1 in the long side direction of the liquid vessel 5a andthe height of liquid L3 of liquid 5b in a stationary condition as shownin FIGS. 3 and 4.) with the primary natural vibration cycle of themultistory building 1, and the vibration energy of the multistorybuilding 1 is absorbed by its wave motion. When the liquid 5b sloshes,the liquid 5b passes the meshes 5c provided in the liquid vessel 5a inthe up and down directions in FIG. 4 as shown by the arrows AR by thesloshing. At the time, viscosity resistance acting between the liquid 5band the meshes 5c acts on the direction in which the movement of theliquid 5b is restrained. Accordingly, the sloshing of the liquid 5b isdamped, and absorbing power of the vibration energy is improved.

When the vibration of the structural body 3 becomes over thepredetermined value, the height of wave of the liquid 5b in the dampingdevice 5 also becomes higher. Then, the apical portion 5j of the wave 5ireaches at the lid member 5g as shown in FIG. 4. However, when theapical portion 5j of the wave directly collides the lid member 5g andbounds, the cycle of the liquid 5b is disturbed, and it becomes to beimpossible to exercise the proper damping effect. But, the wavedissipation devices 5h and 5h are disposed at both sides in thedirection of the wave motion where the apical portion 5j of the wave 5iis produced in the liquid vessel 5a, the wave 5i flows into the manyporosity of the porous member of the wave dissipation device 5h in theshape of dissipating in such a manner that the wave 5i collides the wavedissipation device 5h, and its energy is efficiently absorbed.Therefore, the wave by means of bounce by which wave motion cycle in thevessel is confused dosen't occur. Furthermore, the wave dissipationdevice 5h can prevent wave from colliding the lid member 5g directly.Therefore, the exceeding pressure don't occur in the lid member 5g bythe wave, and the reduction of the lid member 5g can be prevented.Accordingly, the absorbing operation of the vibration by the dampingdevice 5 is smoothly performed.

The above-described embodiment has mentioned the case using the meshes5c as a damping member provided in the liquid vessel 5a. But, anyconfiguration, form, and installation mode of the damping member areavailable as long as the damping member can damp the sloshing of theliquid 5b in the liquid vessel 5a. For example, it may be available thatplural meshes 5c are provided in such a manner that the liquid vessel 5ais divided in the vertical direction in FIG. 6, as shown in FIGS. 5 and6. Furthermore, it is possible that the meshes 5c are provided in theshape of mating the vertical direction with the horizontal direction ofthe liquid vessel 5a as shown in FIGS. 16 and 19. In case that themeshes 5c are provided at both sides of the liquid vessel 5a at level,the height of the wave 5i of the liquid 5b can be restricted by themeshes 5c provided at level. Therefore, the damping efficiency can beexercised toward earthquake occurring the bigger vibration and the like.

And, besides members 5c, partition walls 5d are provided in the shape ofpartitioning in the direction of the wave motion of the liquid 5b in theliquid vessel 5a, that is, in the right and the left direction in thefigure as shown in FIGS. 7 and 8 (The water surface of the wave motion5f is divided into the plural number.). Moreover, many projections 5eare disposed at the partition walls 5d in the shape of fitting sloshingforms of the liquid 5b (namely, for example, in the shape of denting thecenter portion as shown in FIG. 8). Then, the vibration of the liquid 5bis damped by the viscosity resistance occurring between the projections5e and the liquid 5b. The above-described method is naturally available.Moreover, a chip of steel, plastic moulding goods and the like can bedisposed in the liquid vessel 5a as a damping member.

The arrangement forms of the damping devices 5 can be properly selectedaccording to the arrangement place and the necessary damping effect.Since the wave motion of the liquid 5b occurs in the stretcher directionof each damping device 5, the damping devices 5 are disposed in such amanner that the stretcher directions WD of the water surface of the wavemotion 5f of each damping device 5 are faced to at least two directionsof the structure 1 to be absorbed the vibration. Then, the vibrationacts on each damping device 5 in the shape of resolving into twodirections at least, and high damping effect can be exercised. Forexample, as shown in FIGS. 9 and 10, plural damping devices 5 can bearranged so that the stretcher directions WD in which the water surfaceof the wave motion 5f forms the wave motion face two horizontaldirections being orthogonal each other. Accordingly, the vibration intwo orthogonal directions occurring at the structure 1 can beeffectively absorbed. Moreover, as the arrangement form of the dampingdevices 5, many damping devices 5 can be arranged along the externalwall 1a of the structure 1 as shown in FIGS. 11 and 15. (In case of FIG.15, the damping devices are also disposed at the center of the structure1.) In such a case, if there is an existing equipment such as a machineroom of an elevator at the apical portion 3a of the structure 1, thedamping devices 5 can be disposed by avoiding such an existingequipment, and the construction space can be effectively utilized. Incase that the plane form is circular structure 1, many damping devicesmay be disposed along the external wall 1a of the circle as shown inFIG. 12. And, it can be off course that the damping devices 5 aredisposed radially as shown in FIG. 14. Furthermore, the damping effectcan be substantially improved by arranging the damping devices along theexternal wall 1a of a structure 1 at which vibration amplitude becomesbigger.

In case that the position of the center of gravity W of the structuralbody 3 is shifted from the position of the center of rigidity G (In caseof FIG. 17, the position of the center of gravity W locates the centerin up and down directions and in right and left directions in thestructural body 3 in the figure, and the position of the center ofrigidity G locates the center in up and down directions and the righthand to some extent in the figure in comparison with the center ofgravity W.), the structural body 3 generates torsional vibration withthe center of rigidity G as its center in the directions as shown by thearrows A and B. Then, the farther the distance from the center of therigidity G is, the bigger the amplitude of the structural body 3becomes. In case of FIG. 17, the amplitude of the side face 3b of theleft hand in the figure becomes bigger than that of the side face 3c ofthe right hand. Then, since the vibration energy of the side face 3bbecomes bigger than that of the side face 3c, it is necessary that thevibration absorbing ability of the side face 3b side is bigger than thatof the side face 3c side in order to absorb the vibration properly. Whenthe number of the damping devices 5 being disposed at the side face 3bhaving the distance L4 from the center of rigidity G is more than thatbeing disposed at the side face 3c having the distance L3, the absorbingquantity of the vibration energy of the side face 3b side increases. Inresult, the vibration in the directions as shown by the arrows A and Bof the structural body 3 is smoothly and thoroughly absorbed relating toboth sides, the right and the left of the center of rigidity G.

In case that the position of the center of rigidity G is shifted in upand down directions of the structural body 3 as well as in right andleft directions as shown in FIG. 18 (In case of FIG. 18, the position ofthe center of gravity W locates the center in up and down directions andin right and left directions of the structural body 3 in the figure. Theposition of the center of rigidity G locates the upper portion in thefigure to some extent and the right hand than the center of gravity W.),the amplitude of the side face 3b having the distance L4 from the centerof rigidity G and the amplitude of the side face 3e having the distanceL6 from the center of rigidity G become big. Accordingly, the number ofthe damping devices 5 to be disposed on the side faces 3b and 3e sideare more than that on the side faces 3c and 3d side which have thedistances L3 and L5 from the center of rigidity G respectively.Therefore, the vibration absorbing ability of the side faces 3b and 3eside are increased, and the vibration of the structural body 3 issmoothly absorbed without unbalance.

The structure having comparatively long vibration cycle in the flexiblestructure is suitable for the structure to which the damping devices 5according to the present invention are applied. It is off course thatthe tower 6 comprising steel frame and the like as shown in FIG. 13 canbe applied as well as the multistory building 1 as shown in FIG. 1.

The damping effect is exercised in such a manner that concerning thequantity of the liquid 5b in the liquid vessel 5a, the weight of freewater which depends on splash is 0.5-2% of the weight of a structure(The much the weight of free water is, the higher the damping effectis.), and the damping constant by means of the damping member is about2-10%.

The above-described embodiment mentioned with regard to the case thatwave dissipation devices 5h are disposed at both sides in the wavemotion directions WD of the liquid vessel 5a. However, wave dissipationdevices 5h aren't always disposed at the both sides of the liquid vessel5a. Any place is available regarding installation place of wavedissipation devices as long as they aren't always soaked in the liquid5b. It is off course that they can be disposed at all faces of the upperportion or all faces of the sidewall of the liquid vessel 5a.

Furthermore, the plane form of the structure 1 isn't always square formas shown in FIGS. 17 and 18. It is off course that any form, forinstance polygon and orbicularity is available.

The damping devices according to the present invention can be disposedat both structures, a new structure and an existing structure. Forinstance, the damping devices by disposing the damping member such asmeshes in an elevated water tank which is equipped at the upper portionof the existent structure are off course available.

In the modes of vibration which occurs on the structural body 3, thereare the higher-level modes such as the secondary and the tertiary aswell as the primary vibration mode. Those vibration forms are asfollows; In the primary mode, the maximum amplitude portion M1 exists atthe upper edge of the structural body 3 as shown in FIG. 20 (In FIGS. 20through 22, the structural body 3 is indicated by a line in order tounderstand the explanation easily.). However, the secondary vibrationmode is substantially different from the primary one in a mode as shownin FIG. 21, and the maximum amplitude portions M2 and M3 occur not onlyat the upper edge of the structural body 3 but also at the down portionto some extent in comparison with the center portion. Moreover, in thetertiary vibration mode, as shown in FIG. 22, the maximum amplitudeportions M4, M5 and M6 occur at the upper edge of the structural body 3,the upper portion in comparison with the center and the down portion incomparison with the center respectively.

Accordingly, to install the damping devices 5 only on the upper portionof the structural body 3 is available for the primary vibration mode,but it is thinkable that this lacks effectiveness for the secondaryvibration or the higher-level vibration than the secondary.

Therefore, as shown in FIG. 23, the damping devices 5_(A) in which theliquid 5b is stored are disposed at the upper portion of the structuralbody 3, that is, at the maximum amplitude portion M1 in the primarynatural vibration of the structural body 3. In this case, the liquid 5bhas the sloshing cycle corresponding to the primary natural frequency ofthe structural body 3 (Ordinarily, it corresponds with the primarynatural frequency.). Moreover, the damping devices 5_(B) in which theliquid 5b is stored are disposed at the maximum amplitude portions M2and M3 in the secondary natural vibration of the structural body 3. Inthis case, the liquid 5b has the sloshing cycle corresponding to thesecondary natural frequency of the structural body 3 (Ordinarily, itcorresponds with the secondary natural frequency.). The shorter thesloshing cycle of the storing liquid 5b is, that is, the higher thefrequency is, the smaller the liquid vessel 5a comprising the dampingdevices 5 is.

By taking the above-described measures, in the structural body 3 asshown in FIG. 23, the primary vibration is efficiently absorbed by meansof the damping devices 5_(A) and the secondary vibration is efficientlyabsorbed by means of the damping devices 5_(B) in case of earthquake andthe like. Furthermore, in order to improve damping efficiency, thedamping devices 5_(C) in which the liquid 5b is stored are disposed atthe maximum amplitude portions M4, M5 and M6 in the tertiary naturalvibration as shown in FIG. 24 as well as damping actions toward theprimary and the secondary vibration by means of the damping devices5_(A) and 5_(B) as shown in FIG. 23. In this case, the liquid 5b of thedamping devices 5c has the sloshing cycle corresponding to the tertiarynatural frequency of the structural body 3 (Ordinarily, it correspondswith the tertiary natural frequency.). Then, the damping efficiency ofthe structural body 3 is expanded to the tertiary natural vibrationportion.

Heretofore, the present invention was explained on the basis of theembodiments. But, the embodiments which are mentioned in the presentspecification are nothing but instances. And, the embodiments aren'trestricted. The scope of the invention is designated by the claimsaccompanied with the specification and isn't restricted to the mentionsof the embodiments. Therefore, all the deformation and the changebelonging to the claims are included in the scope of the presentinvention.

I claim:
 1. A damping device for absorbing vibrations of a structuresaid damping device comprising:an elongated vessel for containing aliquid therein such that movement of the vessel will create a wavemotion of the liquid surface in the elongated direction of said vessel;a plurality of damping members disposed inside said vessel for dampingthe sloshing of the liquid inside said vessel, said plurality of dampingmembers comprising a plurality of meshes, including one said meshvertically disposed in a central portion of said vessel and horizontalsaid meshes disposed at end portions of said vessel; and wavedissipation means for dissipating the wave motion of the liquid in saidvessel.